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  <div class="section" id="loadcontrol-command">
<h1><span class="section-number">3.2.6.1. </span>LoadControl Command<a class="headerlink" href="#loadcontrol-command" title="Permalink to this headline">¶</a></h1>
<p>This command is used to construct a LoadControl integrator object.</p>
<dl class="function">
<dt>
<code class="sig-name descname">integrator LoadControl $lambda &lt;$numIter $minLambda $maxLambda&gt;</code></dt>
<dd></dd></dl>

<table class="colwidths-given docutils align-default">
<colgroup>
<col style="width: 17%" />
<col style="width: 17%" />
<col style="width: 67%" />
</colgroup>
<thead>
<tr class="row-odd"><th class="head"><p>Argument</p></th>
<th class="head"><p>Type</p></th>
<th class="head"><p>Description</p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><p>$lambda</p></td>
<td><p><em>float</em></p></td>
<td><p>the load factor increment <span class="math notranslate nohighlight">\(\lambda\)</span></p></td>
</tr>
<tr class="row-odd"><td><p>$numIter</p></td>
<td><p><em>integer</em></p></td>
<td><p>the number of iterations the user would like to occur in the solution algorithm. Optional: optional default = 1</p></td>
</tr>
<tr class="row-even"><td><p>$minLambda</p></td>
<td><p><em>float</em></p></td>
<td><p>the min stepsize the user will allow. optional: defualt <span class="math notranslate nohighlight">\(= \lambda_{min} = \lambda\)</span></p></td>
</tr>
<tr class="row-odd"><td><p>$maxLambda</p></td>
<td><p><em>float</em></p></td>
<td><p>the max stepsize the user will allow. optional: default <span class="math notranslate nohighlight">\(= \lambda_{max} = \lambda\)</span></p></td>
</tr>
</tbody>
</table>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>The change in applied loads that this causes depends on the active load patterns (those load patterns not set constant) and the loads in the load patterns. If the only active loads acting on the domain are in load patterns with a Linear time series with a factor of 1.0, this integrator is the same as the classical load control method.</p>
<p>The optional arguments are supplied to speed up the step size in cases where convergence is too fast and slow down the step size in cases where convergence is too slow.</p>
</div>
<div class="section" id="theory">
<h2><span class="section-number">3.2.6.1.1. </span>Theory<a class="headerlink" href="#theory" title="Permalink to this headline">¶</a></h2>
<p>In Load Control the time in the domain is set to <span class="math notranslate nohighlight">\(t + \lambda_{t+1}\)</span> where,</p>
<blockquote>
<div><div class="math notranslate nohighlight">
\[\lambda_{t+1} = \max \left ( \lambda_{min}, \min \left ( \lambda_{max}, \frac{\text{numIter}}{\text{lastNumIter}} \lambda_{t} \right ) \right )\]</div>
</div></blockquote>
<p>where <em>lastNumIter</em> is number of steps required to achieve convergence in the previous step. Changing the step size based on number of iterations in previous step, allows user to reduce the step size when the analysis struggles to converge.</p>
<div class="admonition-example admonition">
<p class="admonition-title">Example</p>
<p>The following example shows how to construct a Load Control Integrator with a step size of <strong>0.1</strong>, which in a static analysis would increment the pseudo time by the <strong>0.1</strong> factor at each analysis step, thus requiring <strong>10</strong> analysis steps if the full load is considered to be applied when the pseudo domain time is <strong>1.0</strong>.</p>
<ol class="arabic simple">
<li><p><strong>Tcl Code</strong></p></li>
</ol>
<div class="highlight-tcl notranslate"><div class="highlight"><pre><span></span><span class="nv">integrator</span> LoadControl <span class="mf">0.1</span>
</pre></div>
</div>
<ol class="arabic simple" start="2">
<li><p><strong>Python Code</strong></p></li>
</ol>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">integrator</span><span class="p">(</span><span class="s1">&#39;LoadControl&#39;</span><span class="p">,</span> <span class="mf">0.1</span><span class="p">)</span>
</pre></div>
</div>
</div>
<p>Code Developed by: <strong>fmk</strong></p>
</div>
</div>


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